[article]
Titre : |
Predicting in-service weatherability of automotive coatings : A new approach |
Type de document : |
texte imprimé |
Auteurs : |
David R. Bauer, Auteur |
Année de publication : |
1997 |
Article en page(s) : |
p. 85-96 |
Note générale : |
Bibliogr. |
Langues : |
Américain (ame) |
Catégories : |
Automobiles -- Revêtements:Automobiles -- Peinture Délaminage Durée de vie (Ingénierie) Photodétérioration Résistance aux conditions climatiques
|
Index. décimale : |
667.9 Revêtements et enduits |
Résumé : |
The prediction of long-term weatherability of coatings has always been a difficult task. This task has been made significantly more difficult by the recent, rapid changes in coatings technology. Conventional weathering protocols which rely on observation of appearance changes after outdoor or laboratory exposures have not always been successful in anticipating in-service failures. This paper discusses the reason for this and describes a new approach for estimating in-service weatherability in coatings. The formalism begins by identifying specific failure modes and developing time-to-failure models which are based on fundamental studies of the chemistry and physics of failure. The statistical variation of the key material, process, and exposure parameters in the failure model are described in terms of distribution functions. Since photooxidation plays a critical role in most weathering issues, a specific distribution function for exposure harshness is estimated that can be used to describe the variation in photooxidation rate under actual in-service conditions. By combining a specific failure model with in-service variations in the key parameters, it is possible to estimate in-service failure rates as a function of material and processing variables, thus, allowing for improved risk assessment of any proposed material or processing change. The formalism also provides clearer direction in the design and use of specific laboratory and outdoor exposures in predicting performance. The method is illustrated by deriving distributions of time-to-failure based on two different hypothetical mechanisms of photo-induced coating delamination. |
Note de contenu : |
- ESTIMATION OF AN EXPOSURE DISTRIBUTION FUNCTION
- DEVELOPMENT OF MODELS OF TIME-TO-FAILURE : Constant UV light transmission - Determination resulting from loss of UVA |
Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=18077 |
in JOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 69, N° 864 (01/1997) . - p. 85-96
[article]
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